Paddy Moloney did his best Lawrence Welk imitation at Riverbend Sunday.

Moloney appeared in his usual role as front man for the Chieftains, the premier traditional-Irish-music group. But the Chieftains were not alone, and Moloney made like the host of a variety show, directing traffic as a cast of singers, a banjo picker, a harp plucker, Canadian tap dancers and more weaved on and off stage. All the auxiliary activity made it easy to forget there was a Chieftains concert happening.

The band is touring in support of its release of last year, Down the Old Plank Road: The Nashville Sessions. The album sets out to illustrate the roots of traditional music of the British Isles in bluegrass and American mountain music and features collaborations with country and bluegrass stars.

Two of those bluegrass players were on hand Sunday: contemporary wiz Tim O'Brien and the colossus of bluegrass banjo, Earl Scruggs.

Scruggs, 79, didn't appear until the back end of the show. He sat in a chair, and his manner was subdued, but his presence was enough to take over the proceedings. In his brief time on stage he left a mark with "Sally Goodin," his Old Plank Road contribution, and his bluegrass standard, "Foggy Mountain Breakdown."

O'Brien played from just about start to finish, backing up the Chieftains on acoustic guitar and mandolin and handling lead vocals on "Cindy" and "Down the Old Plank Road."

Another key contributor was Newport's own Nancy Clark on harp. Derek Bell, the Chieftains' long-time harpist, died in October. Moloney made mention of the loss several times during the 90-minute performance, and his solo lament on the whistle was a beautiful tribute to his band mate and the night's finest moment.

Clark was the featured musician on a three-song block that ended with the classic Irish harp showcase "O'Carolan's Concerto."

A troupe of girls from the McGing School of Irish Dance added more local flavor, and they weren't the only ones dancing. There was a pair of traditional Irish dancers, as well as a Canadian brother team, who, for whatever reason, were on hand to perform what Moloney called Ottawa Valley step dancing.

Nanci Griffith also made an appearance, singing "Ford Econoline" with the Chieftains, which made about as much sense as the Canadian step dancers. Griffith was also the opening act, and she and her band did 50 minutes of her brand of earnest country-folk.